3-Thia-4-arylquinolin-2-one derivatives

ABSTRACT

This invention describes compounds of Formula (I) which are modulators of potassium channels and are useful for treating conditions affected by abnormal potassium channel activity including erectile dysfunction and irritable bowel syndrome.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 60/511,016 filed Oct. 14, 2003.

FIELD OF THE INVENTION

The present invention is generally directed to quinolinone derivatives,and more specifically directed to 3-thia-4-arylquinolin-2-onederivatives.

BACKGROUND OF THE INVENTION

Potassium channels are transmembrane proteins which are ubiquitouslyexpressed in mammalian cells and represent one of the largest and themost diverse group of ion channels from a molecular perspective.Potassium channels play a key role in regulation of cell membranepotential and modulation of cell excitability. Potassium channels arelargely regulated by voltage, cell metabolism, calcium and receptormediated processes. [Cook, N. S., Trends in Pharmacol. Sciences 1988, 9,21; and Quast, U., et al., Trends in Pharmacol. Sciences 1989, 10, 431].Calcium-activated potassium (K_(Ca)) channels are a diverse group of ionchannels that share a dependence on intracellular calcium ions foractivity. The activity of K_(Ca) channels is regulated by intracellular[Ca²⁺], membrane potential and phosphorylation. On the basis of theirsingle-channel conductances in symmetrical K⁺ solutions, K_(Ca) channelsare divided into three subclasses: large conductance (BK or Maxi-K) arethose having a conductance of greater than about 150 picosemens (pS);intermediate conductance are those having a conductance of about 50-150pS; and small conductance are those having a conductance of less thanabout 50 pS. Large-conductance calcium-activated potassium channels arepresent in many excitable cells including neurons, cardiac cells andvarious types of smooth muscle cells. [Singer, J. et al., PflugersArchiv. 1987, 408, 98; Baro, I., et al., Pflugers Archiv. 1989, 414(Suppl. 1), S168; and Ahmed, F. et al., Br. J. Pharmacol. 1984, 83,227].

Potassium ions play a dominant role in controlling the resting membranepotential in most excitable cells and maintain the transmembrane voltagenear the K⁺ equilibrium potential (E_(k)) of about −90 milliVolts (mV).It has been shown that opening of potassium channels shift the cellmembrane potential towards the E_(k), resulting in hyperpolarization ofthe cell. [Cook, N. S., Trends in Pharmacol. Sciences 1988, 9, 21].Hyperpolarized cells show a reduced response to potentially damagingdepolarizing stimuli. Those BK channels which are regulated by bothvoltage and intracellular Ca²⁺ act to limit depolarization and calciumentry and may be particularly effective in blocking damaging stimuli.Therefore cell hyperpolarization via opening of BK channels may resultin protection of neuronal cells, as well as other types of cells, e.g.,cardiac cells. [Xu, W., Liu, Y., Wang, S., McDonald, T., Van Eyk, J. E.,Sidor, A., and O'Rourke, B. Cytoprotective Role of Ca²⁺-activated K⁺Channels in the Cardiac Inner Mitochondrial Membrane. Science 2002, 298,1029-1033].

BK channels have been shown to be one of two physiologically relevantpotassium channels in relaxing human smooth muscle, including bothintestinal and penile smooth muscle. Evidence that relaxation of smoothmuscle is beneficial to irritible bowel syndrome and erectiledysfunction has been reported. See the following references: Christ, G.J. Drug News Perspect. 2000, 13, 28-36; Poynard T. et al. AlimentaryPharmacology and Therapeutics 2001, 15, 355-361; and Argentieri, T. M.U.S. patent application No. 2002/0183395.

A variety of synthetic and naturally occurring compounds with BK openingactivity have been reported. 4-Aryl-3-hydroxyquinolin-2-one derivativesare disclosed in U.S. Pat. No. 5,892,045, issued Apr. 6, 1999; U.S. Pat.No. 5,922,735, issued Jul. 13, 1999; U.S. Pat. No. 6,353,119, issuedMar. 5, 2002. 4-Arylquinolin-2-one derivatives are disclosed in U.S.Pat. No. 6,184,231, published Feb. 6, 2001 and U.S. Pat. No. 5,972,961,published Oct. 26, 1999. See also Hewawasam, P. et. al. J. Med. Chem. 462819-2822 (2003). Other quinolinones are disclosed in U.S. Pat. No.6,538,022; Japanese Pat. No. 2002371078; and PCT patent application WO2002026713.

Despite advances in the art, further advances are needed for compoundscapable of modulating potassium channels, in particular,large-conductance calcium-activated potassium channels. Such compoundswould be useful in treating conditions arising from dysfunction ofcellular membrane polarization and conductance.

SUMMARY OF THE INVENTION

This invention describes 3-thia-4-arylquinolin-2-one compounds havingthe general formula I or pharmaceutically acceptable salts or solvatesthereof,

wherein R, R¹, R², R³, R⁴, R⁵ and R⁶ are as defined below.

The present invention also provides pharmaceutical compositionscomprising these compounds and methods for the treatment of conditionsresponsive to potassium channel activity, such as ischemia, stroke,convulsions, epilepsy, asthma, irritable bowel syndrome, migraine,traumatic brain injury, spinal cord injury, sexual dysfunction andurinary incontinence.

DETAILED DESCRIPTION OF THE INVENTION

The present invention describes novel 3-thia-4-arylquinolin-2-onecompounds and related derivatives of Formula (I) or pharmaceuticallyacceptable salts or solvates thereof

wherein:

-   -   R and R¹ are independently hydrogen or methyl;    -   R², R³, and R⁴ are independently hydrogen, halogen, cyano,        nitro, or trifluoromethyl, provided R², R³, and R⁴ are not all        hydrogen;    -   R⁵ is bromo, chloro, or nitro;    -   R⁶ is SO₂R⁷;    -   R⁷ is C₁₋₆ alkyl, C₁₋₂ fluoroalkyl, C₂₋₆NR⁸R⁹, or NR⁸R⁹;    -   R⁸ and R⁹ are independently hydrogen or C₁₋₆ alkyl;    -   or NR⁸R⁹ taken together form a heterocycle selected from the        group consisting of pyrrolidinyl, piperidinyl,        4-hydroxypiperidinyl, piperazinyl, 4-methylpiperazinyl,        morpholinyl, and thiomorpholinyl.

The present invention also provides a method for the treatment oralleviation of disorders associated with BK channels, such as ischemia,stroke, convulsions, epilepsy, asthma, migraine, traumatic brain injury,spinal cord injury, sexual dysfunction, urinary incontinence andespecially male erectile dysfunction and irritable bowel syndrome whichcomprises administering together with a conventional adjuvant, carrieror dilutent a therapeutically effective amount of a compound of formulaI or a pharmaceutically acceptable salt thereof.

The term “alkyl” includes both straight and branched chain alkyl groups.“Fluoroalkyl” means alkyl groups bearing from 1 to 5 fluorine atoms.Some examples of fluoroalkyl groups include monofluoromethyl,difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, andperfluoroethyl.

The term “atropisomer” refers to a stereoisomer resulting fromrestricted rotation about a single bond where the rotation barrier ishigh enough to permit isolation of the isomeric species.

The invention encompasses all stereoisomers and tautomers, includingatropisomers. Examples of atropisomers and tautomers are shown below.

The terms “racemic mixture” and “racemate” refer to an equimolar ornearly equimolar mixture of two enantiomeric species. In addition, asused herein, the terms “racemic mixture” and “racemate” are intended toinclude equimolar mixtures of the two atropisomers.

The term “pharmaceutically acceptable salt” is intended to includenontoxic salts synthesized from the parent compound which contains abasic or acidic moiety by conventional chemical methods. Generally, suchsalts can be prepared by reacting the free acid or base forms of thesecompounds with a stoichiometric amount of the appropriate base or acidin water or in an organic solvent, or in a mixture of the two;generally, nonaqueous media like ether, ethyl acetate, ethanol,isopropanol, or acetonitrile are preferred. Lists of suitable salts arefound in Remington's Pharmaceutical Sciences, 18th ed., Mack PublishingCompany, Easton, Pa., 1990, p. 1445. Suitable inorganic bases such asalkali and alkaline earth metal bases include metallic cations such assodium, potassium, magnesium, calcium and the like. The compounds of thepresent invention are useful in the form of the free base or acid or inthe form of a pharmaceutically acceptable salt thereof. All forms arewithin the scope of the invention.

The term “halogen” as used herein and in the claims is intended toinclude fluorine, bromine, chlorine and iodine while the term “halide”is intended to include fluoride, bromide, chloride and iodide anion.

The term “therapeutically effective amount” means the total amount ofeach active component that is sufficient to show a meaningful patientbenefit, i.e., amelioration of acute conditions characterized by openersof large conductance calcium-activated K⁺ channels or increase in therate of such conditions. When applied to an individual activeingredient, administered alone, the term refers to that ingredientalone. When applied to a combination, the term refers to combinedamounts of the active ingredients that result in the therapeutic effect,whether administered in combination, serially or simultaneously.

The term “compounds of the invention”, and equivalent expressions, aremeant to embrace compounds of Formula I and include prodrugs,pharmaceutically acceptable salts, and solvates, e.g. hydrates.Similarly, reference to intermediates, whether or not they themselvesare claimed, is meant to embrace their salts, and solvates, where thecontext so permits.

The term “derivative” means a chemically modified compound wherein themodification is considered routine by the ordinary skilled chemist, suchas an ester or an amide of an acid, protecting groups, such as a benzylgroup for an alcohol or thiol, and tert-butoxycarbonyl group for anamine.

The term “solvate” means a physical association of a compound of thisinvention with one or more solvent molecules. This physical associationincludes hydrogen bonding. In certain instances the solvate will becapable of isolation, for example when one or more solvent molecules areincorporated in the crystal lattice of the crystalline solid. “Solvate”encompasses both solution-phase and isolable solvates. Exemplarysolvates include hydrates, ethanolates, methanolates, and the like.

The term “patient” includes both human and other mammals.

The term “pharmaceutical composition” means a composition comprising acompound of the invention in combination with at least one additionalpharmaceutical carrier, i.e., adjuvant, excipient or vehicle, such asdiluents, preserving agents, fillers, flow regulating agents,disintegrating agents, wetting agents, emulsifying agents, suspendingagents, sweetening agents, flavoring agents, perfuming agents,antibacterial agents, antifungal agents, lubricating agents anddispensing agents, depending on the nature of the mode of administrationand dosage forms. Ingredients listed in Remington's PharmaceuticalSciences, 18^(th) ed., Mack Publishing Company, Easton, Pa. (1999) forexample, may be used.

The phrase “pharmaceutically acceptable” is employed herein to refer tothose compounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for use in contactwith the tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem or complicationcommensurate with a reasonable risk/benefit ratio.

The term “pharmaceutically acceptable prodrugs” as used herein meansthose prodrugs of the compounds useful according to the presentinvention which are, within the scope of sound medical judgment,suitable for use in contact with the tissues of humans and lower animalswithout undue toxicity, irritation, allergic response, and the like,commensurate with a reasonable risk/benefit ratio, and effective fortheir intended use, as well as zwitterionic forms, where possible, ofthe compounds of the invention.

The term “prodrugs”, as the term is used herein, are intended to includeany covalently bonded carriers which release an active parent drug ofthe present invention in vivo when such prodrug is administered to apatient. Since prodrugs are known to enhance numerous desirablequalities of pharmaceuticals (i.e., solubility, bioavailability,manufacturing, etc.) the compounds of the present invention may bedelivered in prodrug form. Thus, the skilled artisan will appreciatethat the present invention encompasses prodrugs of the presently claimedcompounds, methods of delivering the same, and compositions containingthe same. Prodrugs of the present invention are prepared by modifyingfunctional groups present in the compound in such a way that themodifications are cleaved, either in routine manipulation or in vivo, toform the parent compound. The transformation in vivo may be, forexample, as the result of some metabolic process, such as chemical orenzymatic hydrolysis of a carboxylic, phosphoric or sulphate ester, orreduction or oxidation of a susceptible functionality. Prodrugs includecompounds of the present invention wherein a hydroxy, amino, orsulfhydryl group is bonded to any group that, when the prodrug of thepresent invention is administered to a patient, it cleaves to form afree hydroxyl, free amino, or free sulfydryl group, respectively.Functional groups which may be rapidly transformed, by metaboliccleavage, in vivo form a class of groups reactive with the carboxylgroup of the compounds of this invention. They include, but are notlimited to such groups as alkanoyl (such as acetyl, propionyl, butyryl,and the like), unsubstituted and substituted aroyl (such as benzoyl andsubstituted benzoyl), alkoxycarbonyl (such as ethoxycarbonyl),trialkylsilyl (such as trimethyl- and triethysilyl), monoesters formedwith dicarboxylic acids (such as succinyl), and the like. Because of theease with which the metabolically cleavable groups of the compoundsuseful according to this invention are cleaved in vivo, the compoundsbearing such groups can act as prodrugs. The compounds bearing themetabolically cleavable groups have the advantage that they may exhibitimproved bioavailability as a result of enhanced solubility and/or rateof absorption conferred upon the parent compound by virtue of thepresence of the metabolically cleavable group. A thorough discussion ofprodrugs is provided in the following: Design of Prodrugs, H. Bundgaard,ed., Elsevier, 1985; Methods in Enzymology, K. Widder et al, Ed.,Academic Press, 42, p. 309-396, 1985; A Textbook of Drug Design andDevelopment, Krogsgaard-Larsen and H. Bundgaard, ed., Chapter 5; “Designand Applications of Prodrugs” p. 113-191, 1991; Advanced Drug DeliveryReviews, H. Bundgard, 8, p. 1-38, 1992; Journal of PharmaceuticalSciences, 77, p. 285, 1988; Chem. Pharm. Bull., N. Nakeya et al, 32, p.692, 1984; Pro-drugs as Novel Delivery Systems, T. Higuchi and V.Stella, Vol. 14 of the A.C.S. Symposium Series, and BioreversibleCarriers in Drug Design, Edward B. Roche, ed., American PharmaceuticalAssociation and Pergamon Press, 1987.

One aspect of the invention are compounds of formula (I) where R ishydrogen.

Another aspect of the invention are compounds of formula (I) where R¹ ishydrogen.

Another aspect of the invention are compounds of formula (I) where R² ishydrogen, R³ is trifluoromethyl, and R⁴ is hydrogen.

Another aspect of the invention are compounds of formula (I) where R⁵ ischloro.

Some compounds of the invention include

-   -   3-[(4-aminophenyl)thio]-4-(5-chloro-2-hydroxyphenyl)-6-(trifluoromethyl)-2(1H)-quinolinone;    -   3-[(4-aminophenyl)thio]-4-(5-chloro-2-hydroxyphenyl)-1-methyl-6-(trifluoromethyl)-2(1        H)-quinolinone;    -   N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]ethanesulfonamide;    -   N-[4-[[4-(5-chloro-2-methoxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-1,1,1-trifluoromethanesulfonamide;    -   N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-1-propanesulfonamide;    -   N′-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-N,N-dimethylsulfamide;    -   N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-1,1,1-trifluoromethanesulfonamide;    -   N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-2,2,2-trifluoroethanesulfonamide;    -   N′-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-1-methyl-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-N,N-dimethylsulfamide;        and    -   N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-4-morpholinepropanesulfonamide;    -   and salts and solvates thereof.

Certain of the compounds of the present invention can exist inunsolvated forms as well as solvated forms including hydrated forms suchas monohydrate, dihydrate, hemihydrate, trihydrate, tetrahydrate and thelike. The products may be true solvates, while in other cases, theproducts may merely retain adventitious solvent or be a mixture ofsolvate plus some adventitious solvent. It should be appreciated bythose skilled in the art that solvated forms are equivalent tounsolvated forms and are intended to be encompassed within the scope ofthe present invention.

Synthetic Methods

The compounds of Formula I may be prepared by various procedures such asthose illustrated herein in the examples and in the Reaction Schemesdescribed in the specific embodiments and variations thereof which wouldbe evident to those skilled in the art.

The following reaction schemes illustrate representative generalprocedures for the preparation of intermediates and methods for thepreparation of compounds of Formula I according to this invention. Itshould also be evident to those skilled in the art that appropriatesubstitution of both the materials and methods disclosed herein willproduce the examples illustrated below and those encompassed by thescope of this invention.

Reagents and conditions: (a) bromoacetyl bromide, pyridine, CH₂Cl₂, 0°C.; (b) NaH, p-nitrothiophenol, III, 0° C. to r.t.; (c) NaOMe, MeI, THF;(d) SnCl₂, EtOH, reflux; (e) BBr₃, CH₂Cl₂, −78° C. to r.t.

Reagents and conditions: (1) RSO₂Cl, CH₂Cl₂, pyridine, r.t. or 80° C.

Biological Methods

Openers of BK channels exert their cellular effects by increasing theopen probability of these channels [Gribkoff, V. K., et al.,Neuroscientist, 7:166-177 (2001); Gribkoff, V. K. et al., Adv.Pharmacol., 37:319-348 (1997); McKay, M. C., et al., J. Neurophysiol.,71: 1873-1882 (1994); and Olesen, S.-P., Exp. Opin. Invest. Drugs, 3:1181-1188 (1994)]. This increase in the opening of individual BKchannels collectively results in the hyperpolarization of cellmembranes, particularly in depolarized cells, produced by significantincreases in whole-cell BK-mediated conductance. Hyperpolarization, inturn, reduces the excitability of nerve and muscle cells, and decreasesthe open probability of voltage-dependent Ca²⁺ channels, effectivelylowering intracellular concentrations of this potentially harmfulcation. The effect on smooth muscle is that of relaxation.

Assay for BK Channel Openers

The ability of the compounds of the invention to open BK channels andincrease whole-cell outward (K⁺) BK-mediated currents was assessed undervoltage-clamp conditions by determining their ability to increase clonedmammalian (mSlo or hSlo) BK-mediated outward current heterologouslyexpressed in Xenopus oocytes [Butler, A., et al., Science 1993, 261,221-224; Dworetzky, S. I., et al., Mol. Brain Res. 1994, 27, 189-193;Gribkoff, V. K., et al., Mol. Pharmacol. 1996, 50, 206-217]. The two BKconstructs employed represent nearly structurally identical homologousproteins, and have proven to be pharmacologically indistinguishable inour tests. To isolate BK current from native (background, non-BK)current, the specific and potent BK channel-blocking toxin iberiotoxin(IBTX) [Galvez, A., et al., J. Biol. Chem. 1990, 265, 11083-11090] wasemployed at a supramaximal concentration, e.g., 50-100 nanomolar (“nM”).The relative contribution of BK channel-mediated current to totaloutward current was determined by subtraction of the current remainingin the presence of IBTX (non-BK current) from the current profilesobtained in all other experimental conditions (control, drug, and wash)[Gribkoff, V. K. et al., Mol. Pharmacol. 1996, 50, 206-217]. It wasdetermined that at the tested concentrations the compounds profiled didnot significantly effect non-BK native currents in the oocytes. Allcompounds were tested in 5-10 oocytes and are reported at the indicatedconcentration of 20 micromolar (“μM”) (or as otherwise indicated); theeffect of the selected compounds of the invention on BK current wasexpressed as the percent of control IBTX-sensitive current at a singletransmembrane voltage (+140 mV) and is listed in Table 1. Recordingswere accomplished using standard two-electrode voltage clamp techniques[Stuhmer, W., et al., Methods in Enzymology, 1992, 207, 319-339];voltage-clamp protocols consisted of 500-750 milliseconds (“ms”)duration step depolarizations, from a holding potential of −60 mV, to afinal voltage up to +140 mV in 20 mV steps. The experimental media(modified Barth's solution) consisted of millimolar (“mM”): NaCl (88),NaHCO₃ (2.4), KCl (1.0), HEPES (10), MgSO₄ (0.82), Ca(NO₃)₂ (0.33),CaCl₂ (0.41); pH 7.5.

Rat Small Intestine

The ability of the compounds of the invention to relax rat smallintestine tissue as a model for the treatment of irritable bowelsyndrome is described as follows. Male rats (Harlan, Sprague Dawley,250-350 g) were sacrificed by decapitation. A portion of small intestine(ileum) was removed and the attached connective tissues and intestinalcontents removed. The ileum was cut into segments of ≦1 cm in length.The segments were mounted longitudinally between fixed hooks in organbaths containing warm (37° C.) physiological salt solution (compositionin mM: NaCl 118.4, KCl 4.7, KH₂PO4 1.2, MgSO₄ 1.2, CaCl₂ 1.8, Glucose10.1, NaHCO₃ 25; gassed with 95% O₂/5% CO₂, pH 7.4). A stable tension of˜1.5 g was maintained in the tissue segments during the equilibrationperiod of 45 minutes. Changes in muscle tension were measured withisometric force transducers (Grass, FT-03C) and recorded usingAcqKnowledge data acquisition system (AcqKnowledge for MP100WS, BiopacSystems Inc., Goleta, Calif.). Compound or vehicle was added in thebaths for 30 minutes. “Zero” active force was established at the end ofthe experiment using nifedipine (20 μM). The effects of compounds orvehicle on force was determined by measuring the integral ofnifedipine-sensitive force (including resting tone and spontaneouscontractions) pre- and 30 min post-compound (or vehicle) addition.Results are expressed as the percentage inhibition of force. DMSOvehicle inhibited force (integral) by −0.6±3.0% (n=25). Results aresummarized in Table 1.

Rabbit Corpus Cavernosum

The ability of the compounds of the invention to relax rabbit corpuscavernosum tissue as a model for the treatment of erectile dysfunctionis described as follows. New Zealand white rabbits (3.4-3.7 kg) wereeuthanized by sodium pentobarbital (100 mg/kg) overdose. The penis fromeach animal was rapidly removed and immersed in a cold oxygenatedmodified Krebs Henseleit bicarbonate buffer. The penis' outer tunica wasremoved and the corpus cavernosum smooth muscle obtained and cut intostrips approximately 3-5 mm long. The strips were suspended in tissuebaths containing physiological salt solution (see above), and allowed toequilibrate for at least one hour under resting tension of 1.0 gram.Isometric force was measured as described above. Tissue strips werestimulated with the (x-agonist phenylephrine (3 μM) and allowed to reacha steady level of force prior to the addition of test compounds. Theresults are expressed as the percentage inhibition ofphenylephrine-induced force as compared to vehicle control. Results aresummarized in Table 1. TABLE 1 % % % Inhibition Inhibition MaxiK offorce of force opening (RCC (RSI Ex Structure * strips) strips) 1

392 27 10 2

144 7 3

296 4

235 21 5

255 6

222^(⋄) 7

277 32 51 8

170 9

114⁵⁶⁶ 10

354 35*at 20 μM (unless otherwise indicated) expressed as percent increaseover BK current in controls, voltage step to +140 mV^(⋄)at 1 μM.

The results of the above biological tests demonstrate that the compoundsof the invention are potent openers of large-conductancecalcium-activated K⁺ channels (BK or Maxi-K channels) and are effectiveat relaxing intestinal and penile smooth muscle.

Pharmaceutical Compositions and Methods of Use

The compounds of the present invention are useful for the treatment ofpatients for conditions arising from dysfunction of cellular membranepolarization and conductance and are indicated for the treatment ofischemia, stroke, convulsions, epilepsy, asthma, migraine, traumaticbrain injury, spinal cord injury, sexual dysfunction, urinaryincontinence and especially male erectile dysfunction and irritablebowel syndrome, as well as other disorders sensitive to BK channelactivity. Accordingly, in one aspect of the present invention, there isprovided a method of treatment or prevention of conditions responsive toopening of potassium channels in a patient in need thereof, whichcomprises administering to the patient a therapeutically effectiveamount of a compound of Formula I or a pharmaceutically acceptable salt,solvate or prodrug thereof. In another aspect, this invention provides amethod for the treatment of or protection from disorders which aremediated by opening of the large conductance calcium-activated K⁺channels in a patient in need thereof, which comprises administering tothe patient a therapeutically effective amount of a compound of FormulaI or a pharmaceutically acceptable salt, solvate or prodrug thereof.Preferably, the compounds of Formula I are useful in the treatment ofischemia, stroke, convulsions, asthma, irritable bowel syndrome,migraine, traumatic brain injury, urinary incontinence, irritable bowelsyndrome, and sexual dysfunction in both men (erectile dysfunction, forexample, due to diabetes mellitus, spinal cord injury, radicalprostatectomy, psychogenic etiology or any other cause) and women byimproving blood flow to the genitalia, especially the corpus cavernosum,and other disorders sensitive to BK channel activating activity.

In another aspect, this invention provides pharmaceutical compositionscomprising at least one compound of Formula I and a carrier.

The pharmaceutical compositions include suitable dosage forms for oral,parenteral (including subcutaneous, intramuscular, intradermal andintravenous) bronchial or nasal administration. Thus, if a solid carrieris used, the preparation may be tableted, placed in a hard gelatincapsule in powder or pellet form, or in the form of a troche or lozenge.The solid carrier may contain conventional excipients such as bindingagents, fillers, tableting lubricants, disintegrants, wetting agents andthe like. The tablet may, if desired, be film coated by conventionaltechniques. If a liquid carrier is employed, the preparation may be inthe form of a syrup, emulsion, soft gelatin capsule, sterile vehicle forinjection, an aqueous or non-aqueous liquid suspension, or may be a dryproduct for reconstitution with water or other suitable vehicle beforeuse. Liquid preparations may contain conventional additives such assuspending agents, emulsifying agents, wetting agents, non-aqueousvehicle (including edible oils), preservatives, as well as flavoringand/or coloring agents. For parenteral administration, a vehiclenormally will comprise sterile water, at least in large part, althoughsaline solutions, glucose solutions and like may be utilized. Injectablesuspensions also may be used, in which case conventional suspendingagents may be employed. Conventional preservatives, buffering agents andthe like also may be added to the parenteral dosage forms. Particularlyuseful is the administration of a compound of Formula I directly inparenteral formulations. The pharmaceutical compositions are prepared byconventional techniques appropriate to the desired preparationcontaining appropriate amounts of the active ingredient, that is, thecompound of Formula I according to the invention.

The dosage of the compounds of Formula I to achieve a therapeutic effectwill depend not only on such factors as the age, weight and sex of thepatient and mode of administration, but also on the degree of potassiumchannel activating activity desired and the potency of the particularcompound being utilized for the particular disorder of diseaseconcerned. It is also contemplated that the treatment and dosage of theparticular compound may be administered in unit dosage form and that theunit dosage form would be adjusted accordingly by one skilled in the artto reflect the relative level of activity. The decision as to theparticular dosage to be employed (and the number of times to beadministered per day) is within the discretion of the physician, and maybe varied by titration of the dosage to the particular circumstances ofthis invention to produce the desired therapeutic effect.

A suitable dose of a compound of Formula I or pharmaceutical compositionthereof for a mammal, including man, suffering from, or likely to sufferfrom any condition as described herein is an amount of active ingredientfrom about 0.01 micrograms per kilogram (μg/kg) to 50 milligrams perkilogram (mg/kg) body weight and preferrably, from about 0.1 μg/kg to 5mg/kg body weight for oral administration. For parenteraladministration, the dose may be in the range of 0.1 μg/kg to 1 mg/kgbody weight for intravenous administration. The active ingredient willpreferably be administered in equal doses from one to four times a day.However, usually a small dosage is administered, and the dosage isgradually increased until the optimal dosage for the host undertreatment is determined.

The compounds of the present invention may be employed alone or incombination with other suitable therapeutic agents useful in thetreatment of the dysfunction of cellular membrane polarization andconductance, e.g., sexual dysfunction such as cyclic guaminemonophosphate, phosphodiaterase (cGMP PDE) inhibitors and particularlycGMP PDE V inhibitors such as sildenafil. Exemplary of the therapeuticagents are PDE V inhibitors selected from imidazo-quinazolines (see WO98/08848), carbazoles (see WO 97/03675, WO 97/03985 and WO 95/19978),imidazopurinones (see WO 97/19947), benzimidazoles (see WO 97/24334),pyrazoloquinolines (see U.S. Pat. No. 5,488,055), anthranilic acidderivatives (see WO 95/18097), fused heterocycles (see WO 98/07430) andthienopyrimidines (see DE 19632423). Alosetron hydrochloride can becombined with the compounds of the present invention to treat irritablebowel syndrome (see, e.g., U.S. Pat. Nos. 5,360,800 and 6,284,770).

The amount of compound actually administered will be determined by aphysician using sound medical judgement.

DESCRIPTION OF SPECIFIC EMBODIMENTS

The following examples are given by way of illustration and are not tobe construed as limiting the scope of the claims which follow.

In the following examples, all temperatures are given in degreesCentigrade. Melting points were recorded on a Gallenkamp capillarymelting point apparatus are uncorrected. Proton magnetic resonance (¹HNMR) spectra were recorded on a Bruker AC 300 or 500 megaHertz (“MHz”)spectrometer. All spectra were determined in the solvents indicated andchemical shifts are reported in δ units downfield from the internalstandard tetramethylsilane (TMS) and interproton coupling constants arereported in Hertz (Hz). Splitting patterns are designated as follows: s,singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broadpeak; dd, doublet of doublet; bd, broad doublet; dt, doublet of triplet;bs, broad singlet; dq, doublet of quartet. Infrared (IR) spectra usingpotassium bromide (KBr) were determined on a Perkin Elmer 781spectrometer from 4000 cm⁻¹ to 400 cm⁻¹, calibrated to 1601 cm⁻¹absorption of a polystyrene film and reported in reciprocal centimeters(cm⁻¹). Low resolution mass spectra (MS) and the apparent molecularweight (MH⁺) or (M−H)⁻ was determined on a Finnigan TSQ 7000. LC-MSanalysis were carried out on a Shimadzu instrument using one of thefollowing methods (1) YMC ODS C18 column (4.6×33 mm) employing a 4 minlinear gradient of 0% to 100% solvent B in A and a 1 min hold at 100% B(2) YMC ODS C18 column (4.6×30 mm) employing a 2 min linear gradient of0% to 100% solvent B in A and a 1 min hold at 100% B (3) YMC ODS C18column (3.0×50 mm) employing a 2 min linear gradient of 0% to 100%solvent B in A and a 1 min hold at 100% B (4) YMC ODS. C18 column(3.0×50 mm) employing a 4 min linear gradient of 0% to 100% solvent B inA and a 1 min hold at 100% B. In all cases solvent A: 10% methanol, 90%water, 0.1% TFA; and solvent B: 90% methanol, 10% water, 0.1% TFA withUV detector set at 220 nm. The element analyses are reported as percentby weight. Unless otherwise indicated in the Specific Embodiments, R²and R⁴ are H in the descriptive title of the Examples.

Intermediates of Formula (III)

Intermediate 1

2-Bromo-N-[2-(5-chloro-2-methoxy-benzoyl)-4-trifluoromethyl-phenyl]-acetamide.To a solution of(2-Amino-5-trifluoromethyl-phenyl)-(5-chloro-2-methoxy-phenyl)-methanone(IV) (14.13 g, 42.9 mmol, 1 eq) in Dichloromethane (120 mL) at 0° C. wasadded pyridine (4.65 mL, 57.5 mmol, 1.34 eq), then Bromoacetyl bromide(4.98 mL, 57.2 mmol, 1.33 eq). After 3 h, the reaction was quenched withSodium bicarbonate (aq) and extracted three times into Dichloromethane.The combined organic layers were dried over Magnesium sulfate, filteredand concentrated in vacuo. The product was used without furtherpurification.

¹H NMR (300 MHz, CDCl3) δ 12.18 (s, 1H), 8.88 (d, J=8.9 Hz, 1H), 7.82(dd, J=1.9, 8.9 Hz, 1H), 7.71 (d, J=1.9 Hz, 1H), 7.51 (dd, J=2.6, 8.9Hz, 1H), 7.41 (d, J=2.6 Hz, 1H), 6.97 (d, J=8.9 Hz, 1H), 4.08 (s, 2H),3.70 (s, 3H).

Intermediates of Formula (II) Intermediate 2

4-(5-Chloro-2-methoxy-phenyl)-3-(4-nitro-phenylsulfanyl)-6-trifluoromethyl-1H-quinolin-2-one.To a solution of 4-nitrothiophenol (8.73 g, 56.3 mmol, 2.5 eq) in THF(140 mL) at 0° C. was added Sodium hydride (2.26 g, 60% dispersion inmineral oil, 56.5 mmol, 2.5 eq). After stirring for 15 min, a solutionof III (10.15 g, 22.5 mmol, 1 eq) in THF (50 mL) was added rapidlydropwise to the blood-red solution. After 5 min, the ice bath wasremoved, and the solution stirred for 3 h at room temperature. Thereaction was quenched with 1 M HCl, and extracted three times intoEtOAC. The combined organic layers were dried over Magnesium sulfate,filtered, and concentrated in vacuo. Chromatography (2:1, 1:1Hexane:EtOAc) provided pure II in quantitative yield.

¹H NMR (300 MHz, CDCl3) δ 12.64 (s, 1H), 8.06 (d, J=8.9 Hz, 2H), 7.68(d, J=7.1 Hz, 1H), 7.47 (dd, J=2.6, 8.9 Hz, 1H), 7.38-7.31 (m, 4H), 7.12(d, J=2.6 Hz, 1H), 6.97 (d, J=8.9 Hz, 1H), 3.64 (s, 3H).

Intermediate 3

4-(5-Chloro-2-methoxy-phenyl)-1-methyl-3-(4-nitro-phenylsulfanyl)-1H-quinolin-2-one.To a suspension of NaOMe (64 mg, 1.2 mmol) in THF (10 mL) was added II(R1=H) (500 mg, 0.99 mmol). The mixture was stirred for 0.5 h at roomtemperature, at which time methyl iodide (760 μL, 12 mmol) was added.After 18 h, the mixture was concentrated in vacuo. Brine and ethylacetate were added, and the mixture extracted three times with ethylacetate. The organic extracts were dried over magnesium sulfate,concentrated in vacuo, and purified by silica gel chromatography toprovide pure II (R1=Me), (350.4 mg, 68% yield).

EXAMPLE 1

3-[(4-Aminophenyl)thiol-4-(5-chloro-2-hydroxyphenyl)-6-(trifluoromethyl)-2(1H)-quinolinone.To a solution of II (2.07 g, 4.09 mmol, 1 eq) in EtOH (21. mL) was addedSnCl2 (4.56 g, 24.0 mmol, 5.9 eq), and the resulting suspension heatedto reflux for 3 h. After cooling to room temperature, the mixture wasadded to ice, and Sodium bicarbonate was added. The mixture wasfiltered, extracted to EtOAc, and dried over Magnesium sulfate.Concentration in vacuo followed by recrystallization in EtOAc/Hexaneprovided Ia (1.28 g, 66%).

EXAMPLE 2

3-[(4-Aminophenyl)thio]-4-(5-chloro-2-hydroxyphenyl)-1-methyl-6-(trifluoromethyl)-2(1H)-quinolinone.To a solution of Ia (R=Me) (509 mg, 1.07 mmol, 1 eq) in methylenechloride (30 mL) at −78° C. was added a 1M solution of boron tribromidein methylene chloride (6 mL, 6 mmol, 5.6 eq). The solution was broughtto room temperature and stirred for 60 h. The solution was cooled to−78° C. and quenched with saturated aqueous sodium bicarbonate,extracted with ethyl acetate, dried over magnesium sulfate, andconcentrated in vacuo. Silica gel chromatography (ethyl acetate, thenmethanol/methylene chloride) provided the desired material Ia (R=H).

EXAMPLE 3

N-[4-[[4-(5-Chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]ethanesulfonamide.To a solution of3-(4-Amino-phenylsulfanyl)-4-(5-chloro-2-methoxy-phenyl)-6-trifluoromethyl-1H-quinolin-2-oneor3-(4-Amino-phenylsulfanyl)-4-(5-chloro-2-hydroxy-phenyl)-6-trifluoromethyl-1H-quinolin-2-one(49.0 mg, 103 μmol, 1 eq) in pyridine (50 μL) and methylene chloride(500 μL) was added the appropriate sulfonyl chloride (422 μmol, 4.1 eq),and the mixture stirred overnight at room temperature, or at 80° C. inthe absense of methylene chloride for difficult cases. The pyridine wasremoved in vacuo, and 4 N NaOH was added. The suspension was dilutedwith water, washed with chloroform, and adjusted to pH 5 with 1 M HCl.The product was extracted into a mixture of EtOAc and methylenechloride, dried with Magnesium sulfate, and concentrated in vacuo. Finalpurification was effected by reverse phase HPLC to afford pure Ib. ¹HNMR (300 MHz, CDCl3) δ 11.04 (s, 1H), 8.90 (s, 1H), 7.67 (d, J=8.6 Hz,1H), 7.43 (s, 1H), 7.40-7.30 (m, 2H), 7.30-7.24 (m, 3H), 7.11 (d, J=2.5Hz, 1H), 6.98 (d, J=8.7 Hz, 1H), 6.91 (d, J=8.7 Hz, 2H), 2.99 (q, J=7.4Hz, 2H), 1.21 (t, J=7.4 Hz, 3H); LCMS (M+H) 555, RT=3.177 (Method 1).

Examples 4-10 were prepared by similar methods. Retention HPLC timeMethod MS Example Structure (min) ** (M⁺) 4

3.780 1 609 5

3.353 1 569 6

3.233 1 570 7

3.510 1 595 8

3.320 1 609 9

3.253 1 584 10

3.590 1 654** (1) YMC ODS C18 column (4.6 × 33 mm) employing a 4 min lineargradient of 0% to 100% solvent B in A and a 1 min hold at 100% B (2) YMCODS C18 column# (4.6 × 30 mm) employing a 2 min linear gradient of 0% to 100% solventB in A and a 1 min hold at 100% B (3) YMC ODS C18 column (3.0 × 50 mm)employing a 2 min # linear gradient of 0% to 100% solvent B in A and a 1min hold at 100% B (4) YMC ODS C18 column (3.0 × 50 mm) employing a 4min linear gradient of 0% to 100% solvent # B in A and a 1 min hold at100% B. In all cases solvent A: 10% methanol, 90% water, 0.1% TFA; andsolvent B: 90% methanol, 10% water, 0.1% TFA with UV detector set at 220nm.

Although the invention has been described with respect to specificaspects, those skilled in the art will recognize that other aspects areintended to be included within the scope of the claims which follow.Other substituents substantially equivalent to the specific substituentsdescribed herein, e.g., R, R¹, R², R³, R⁴, R⁵, can be employed withinthe scope of the invention.

1. A compound of Formula (I)

wherein: R and R¹ are independently hydrogen or methyl; R², R³, and R⁴are independently hydrogen, halogen, cyano, nitro, or trifluoromethyl,provided R², R³, and R⁴ are not all hydrogen; R⁵ is bromo, chloro, ornitro; R⁶ is SO₂R⁷; R⁷ is C₁₋₆ alkyl, C₁₋₂ fluoroalkyl, C₂₋₆NR⁸R⁹, orNR⁸R⁹; R⁸ and R⁹ are independently hydrogen or C₁₋₆ alkyl; or NR⁸R⁹taken together form a heterocycle selected from the group consisting ofpyrrolidinyl, piperidinyl, 4-hydroxypiperidinyl, piperazinyl,4-methylpiperazinyl, morpholinyl, and thiomorpholinyl; or apharmaceutically acceptable salt or solvate thereof.
 2. A compound ofclaim 1 where R² is hydrogen, R³ is trifluoromethyl, and R⁴ is hydrogen.3. A compound of claim 1 where R is hydrogen.
 4. A compound of claim 1where R¹ is hydrogen.
 5. A compound of claim 1 where R⁵ is chloro.
 6. Acompound of claim 1 selected from the group consisting ofN-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]ethanesulfonamide;N-[4-[[4-(5-chloro-2-methoxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-1,1,1-trifluoromethanesulfonamide;N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-1-propanesulfonamide;N′-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-N,N-dimethylsulfamide;N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-1,1,1-trifluoromethanesulfonamide;N-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-2,2,2-trifluoroethanesulfonamide;N′-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-1-methyl-2-oxo-6-(trifluoromethyl)-3-quinolinyl]thio]phenyl]-N,N-dimethylsulfamide;andN-[4-[[4-(5-chloro-2-hydroxyphenyl)-1,2-dihydro-2-oxo-6-(trifluoromethyl)-3-quinolinyllthio]phenyl]-4-morpholinepropanesulfonamide;or a pharmaceutically acceptable salt or solvate thereof.
 7. Apharmaceutical composition comprising a therapeutically effective amountof a compound of claim 1 and a pharamceutically acceptable carrier.
 8. Amethod of modulating potassium channels comprising administering atherapeutically effective amount of a compound of claim 1 to a patientsuffering from a condition which can be treated by the modulation ofpotassium channels.
 9. The method of claim 8 where the condition iserectile dysfunction.
 10. The method of claim 8 where the condition isirritable bowel syndrome.